This paper is divided into two parts. The first analyses the Spanish defence investment budget. This study identifies important financial problems. In an overall context of budget restrictions, Spanish defence expenditures are going to increase due to the transition to an all‐volunteer recruitment system together with the necessity of modernizing an obsolete armament. In the second part, the Spanish defence budget is compared with other of NATO and European non‐NATO countries. Spain is classified in the same group as Portugal, Greece and Turkey. Although Spain has begun its transition to an all‐volunteer recruitment system, it still retains the characteristic of a compulsory one. After studying the relation between defence budget per soldier and its components with several variables, we can conclude that there is no relation between professionalizing the armed forces and the increase of armament expenditure per soldier. That conclusion is important for the Spanish budget restriction.